3. Computer controlled cutting¶

This week focused on understanding and working with laser cutters and vinyl cutters.

What is computer controlled cutting?

Computer-controlled cutting is a way of cutting or engraving materials using machines that follow a digitally designed file. Instead of cutting by hand, a computer tells the machine exactly where to cut, how deep, and how fast. This makes the process more accurate, faster, and easier, especially for complex shapes.

Part 1: Exploring Vinyl Cutter¶

For this part of the assignment, I worked with the Graphtec CE7000. This was a new machine for me, and I had never explored it before. Understanding its features, settings, and workflow was an exciting learning experience. Unlike laser cutting, which burns through materials, a vinyl cutter uses a sharp blade to slice through thin films with extreme accuracy.

Setting up the machine

Before cutting anything, I had to understand how to load materials, adjust blade settings, and avoid errors.

Loading the Material¶

The Graphtec CE7000 supports both roll-fed and sheet-fed materials. I started with a roll, which meant properly feeding it into the machine.

Start by unlocking the back lever of the machine, which releases the pinch rollers (the wheels that hold the material in place). Then, place the material on the machine bed, making sure it was aligned between the two blue markers. Lock the material in place so it doesn’t shift during cutting.

A few things I learned while positioning the material:

The vinyl should be flat and not skewed; otherwise, it shifts while cutting.
After adjusting, I locked the lever back down and pressed the "Scan" button to let the machine detect the material size.
Error I got: Realign the push rollers.This happened because the pinch rollers were not properly positioned within the designated marked areas on the machine.

About the blade¶

Since the machine relies on a stainless steel blade, getting the right blade depth was key.

Turn clockwise - Lowers the blade for thicker materials.
Turn counterclockwise - Raise the blade for thinner materials.

The blade adjustment is crucial because:

Too much depth - The blade cuts through the backing and ruins the material.
Too little depth - The blade doesn’t cut through at all, leaving an incomplete design.

Once the vinyl was loaded and the blade was adjusted, I needed to set up the machine settings correctly to ensure a clean and precise cut.

Understanding the Cutting Conditions:

Speed – Controls how fast the blade moves.
Force – Adjusts the pressure applied by the blade.
Offset – Fine-tunes blade alignment for sharper corners.
Acceleration – Determines how quickly the blade starts/stops.

Performing a Test Cut Before starting with the full cut you must always do a test cut

On the machine’s display, go to Menu > Test Cut.
The machine will cut a small triangle inside a square.
Peel the triangle: If it lifts easily without cutting through the backing, the settings are correct

Graphtec Studio 2¶

You can download Graphtec Studio 2 from the official Graphtec website. It’s available for both Windows and Mac. Link to download

Setting Up a File Click File > Import and select the SVG, DXF, AI, or PDF file. If using a PNG or JPG, use the Trace Tool to convert the image into vector lines. (The best option)

How is Image Tracing Useful?

This feature automatically creates cut lines around any image, making it super useful when working with logos, graphics, or text-based designs that are not already in vector format.

Exporting & Sending the Design to the Cutter

Since Graphtec Studio 2 supports multiple machines, I had to make sure I was sending the job to the correct cutter model.

Go to File > Output (or click the Cut icon).
In the Device Selection dropdown, choose Graphtec CE7000.
Ensure the USB cable is properly connected (or the cutter is detected over the network, if using LAN).
Checking the Media Size (Poll Size): Before cutting, it’s crucial to make sure the design fits within the material loaded on the machine. This is done using the Poll Size feature.

What is Poll Size?

Poll Size automatically detects how much material (length) is loaded in the cutter. t prevents errors like cutting outside the media area.

Then Send the File and click on ok

Difference between Send a Copy vs. Output

Send a Copy - This allows you to send a duplicate of the file to the machine while keeping a backup in the software.
Output - Sends the file immediately to the cutter and starts the cutting process.

Note: Choose Output if you're ready to cut immediately and choose Send a Copy if you plan to adjust settings or test a prototype first

Final Outcome

After setting up the file and sending it to the cutter, I successfully cut my design on vinyl. Below is the final output of the vinyl cut

Vinyl on a T-shirt¶

I wanted to explore how vinyl could be used on textiles, so I decided to transfer my cut design onto a T-shirt. My friend Samruddhi and I worked on this together. We chose our sir's favorite quote Dive to Rise, and got to work.

Designing in Graphtec Studio 2

Instead of designing in external software, we thought, why not do everything in Graphtec Studio 2 itself? We tested various fonts, including both thick and thin strokes, to see how well they look on the fabric. To modify individual letters, adjusting spacing and alignment we used the group and ungroup functions

Once satisfied with the design, we exported the file and sent it to the cutter.

Cutting & Weeding the Design¶

Once the vinyl was cut, we first transferred it onto a transparent sheet to keep the design intact. Then we carefully weeded out the excess material, ensuring only the intended design remained.

Since we chose a single font style, we focused on how fine details and sharp edges would transfer onto fabric.

Transferring the Vinyl onto Fabric¶

Now for the fun (and slightly nerve-wracking) part—transferring the vinyl onto fabric. We carefully placed the design where we wanted it and pressed it down, hoping it would stick. When we peeled off the backing paper, the vinyl didn’t come off as easily as we expected, which made us panic for a moment! But then we applied heat to it, pressing it down. Some areas needed a little extra heat, so we pressed them again to make sure everything was securely in place. After that, the vinyl stayed in place, and we felt a huge sigh of relief.

The final result

We had a lot of laughs along the way, and in the end, we were super happy with how it turned out!

Exploring Origami¶

After completing the vinyl design on the T-shirt, I thought it would be fun to challenge myself further by integrating origami into the process.

What is Origami? Origami is the Japanese art of folding paper to create intricate shapes and figures, typically without the use of glue or scissors

Drawing the Design The first step was to create a precise design in Adobe Illustrator. I drew a V-fold pattern, thinking about how I could transfer that design on the material

Transferring to Vinyl Cutter

After finalizing the design in Illustrator, I exported the file and sent it to the vinyl cutter. And then, of course, I crossed my fingers and hoped everything would go smoothly! But, as with most things in life, it wasn’t quite that simple. An error popped saying the cutter is not ready. So, after a little troubleshooting and some "please work" vibes, I fingered out that the USB cable was loose. After plugging it in securely the cutter finally came to life.

First Attempt: The Cut Tore the Paper

I was super excited to send the file to the cutter. But as soon as I got the paper loaded, it was time for the first test!

Result: The paper tore. The cutter’s blade went too deep into the paper, causing the cuts to rip the material instead of leaving crisp lines. Not a great start, but a good lesson in adjusting the blade depth!

Second Attempt: Cuts Too Shallow, Didn’t Fold Properly No worries, I thought, let’s try again—this time adjusting the blade depth and cutting force. I reduced the pressure, thinking it would prevent tearing.

Result: The cut wasn’t deep enough. I tried to fold it, the edges just didn’t cooperate. The folds were uneven, and the cuts didn’t work as intended. This was a bit frustrating.

The perfect cut After a few more tweaks, I finally found the sweet spot for the half-cuts. The blade was adjusted just right—deep enough to cut through the paper, but shallow enough to leave the backing intact. Success!

Part 2: Exploring Laser Cutter¶

Understanding the machine¶

Our laser cutter machine at riidl is a CO2 Laser cutter by SLA (Suresh Indu Lasers Pvt. Ltd). The machine works by directing a strong beam of light through mirrors and lenses, which focus it on the material. The heat from the laser melts or burns the material, creating clean cuts or engraved designs.

How the CO₂ Laser Cutter Works?

At the back of the machine, there is a long glass tube filled with CO₂ gas. When electricity passes through the tube, it excites the gas and generates a laser beam. This beam then travels through a series of mirrors that directs it to the cutting head. A lens in the cutting head focuses the laser beam onto the material, allowing for precise cutting and engraving.

Cooling System

Since the CO₂ tube generates a lot of heat while the laser is in use, it needs a cooling system to prevent overheating. Water flows around the CO₂ tube inside the machine, absorbing heat and keeping the system at a stable temperature. The water is circulated continuously.

Exhaust System

When cutting materials, the laser produces smoke and fumes. The machine has an exhaust system with a fan that removes the smoke and sends it outside. Proper ventilation is essential, especially when cutting materials like acrylic, which produce strong fumes. If the exhaust system is not working properly, smoke can build up inside the machine, affecting the quality of the cut and creating safety hazards.

The Laser Cutter Bed

The bed of the laser cutter is where materials are placed for cutting or engraving. Our machine has a 3 x 4 ft bed size. It is essential to ensure that the bed is level to achieve accurate cuts.

To check if the bed is straight, we used a spirit level (the liquid-filled leveling tool). This helps confirm that the surface is even, preventing uneven cuts or inconsistent engraving depth.

Group Work

Along with my Fab Academy peers — Samrudhi Rovalekar, Sohan Suryavanshi, Mihir Shah , and Devanshi Mengar. Later, my friend Samrudhi Rovalekar and I, as a group, worked on calculated focus of the laser cutter and the the kerf.

Safety Training¶

Stay with the Machine – Never leave it unattended. (Fire is not part of the design process.) Always know where the emergency stop button is—just in case things go wrong. Check the Bed – Make sure the bed is clean and free from leftover materials. A small piece of burnt wood can catch fire and ruin your work (or worse, the machine). Close the Machine Cover – Never operate with the lid open!

Setting up the machine¶

To start using the laser cutter, follow these steps:
Turn on all power units of the laser cutter machine (the machine itself, the coolant and the exhaust)
Place your material of the bed (Size of the bed: 3*4ft)
After the material is loaded of the bed adjust the Z axis according to the focus
Set the cutting parameter (power, speed, and frequency settings)
Then set the XY origin of the plane and click on origin’
Don’t forget to pulse to check where exactly your origin is.
Do a frame check to get an idea if your design is within the boundaries of the material. And then start your process.

Understanding Laser Cutting Parameters To get the best results from our laser cutter, we tested and documented several important parameters:

Finding the Focus¶

Focus is the point where the laser beam is most concentrated. When the laser is perfectly focused, the beam is thinnest and most powerful, allowing for sharp engravings, clean cuts, and minimal material burning.

The Triangle Test

We designed a right-angled triangle.The triangle had:
One edge resting on the laser bed (zero height)
One edge gradually increasing in height
A long sloped surface (hypotenuse) for the laser to move across

We positioned this triangle on the bed in such a way that the laser would move in a straight horizontal line from the lowest to the highest point. As the laser passed over the triangle, it naturally tested different focal distances in a single pass.

Breaking Down the Process

To refine our focus further, we broke down our testing process into four key steps. The following image summarizes our approach, from initial test cuts to final adjustments.

Step 1: Initial Test Cuts We started by making three vertical test cuts on different areas of the sloped surface. This gave us a rough idea of where the laser focus might be, but it wasn’t precise enough.

Step 2: Refining the Focus

To improve accuracy, we performed a final single test cut where the previous cuts looked sharpest. The results showed some improvement, but the lines were still slightly blurry in certain areas.

Step 3: Horizontal Fine-Tuning

To pinpoint the best focus, we made a series of horizontal test cuts, spaced closely together along the slope. This helped us identify the exact region where the laser produced the thinnest, most defined cut, indicating the optimal focal distance.

Step 4: Adjusting Speed & Power Settings

Once we had a rough focus, we tested different power and speed settings: * Power: 10-15, Speed: 40 – The cuts were visible but slightly inconsistent. * Increasing Speed While Keeping Power Constant – This resulted in finer, more precise lines, helping us confirm the exact focus point.

Slope Calibration – 5mm Incline

Calculating the Actual Focus Distance

Alright, so we had a pretty good idea of where the laser was focusing thanks to our 5mm slope calibration, but we wanted to be extra sure. Now it was time to determine the exact focal length using some geometry.

Since our slope was 5mm, we treated it as a right-angled triangle and applied the Pythagorean theorem and Isometric triangle theorem to calculate the laser’s exact focal point.

After all the calculations and test observations, we found that the final focus was 6.03mm. This means that for the best cutting and engraving results, the material should always be positioned exactly 6.03mm from the laser head.

Final focus: 6.03mm

Measuring the Kerf¶

Kerf is the tiny gap that a laser cutter burns away when cutting a material. Since the laser removes some material, the final piece is always a little smaller than the design. This means that if you don’t account for kerf, pieces might not fit together properly.

To measure the kerf, I first designed and cut a comb-like test piece. Once the file was ready I laser cut it on an acrylic sheet by keeping the speed 10 and min power 60 and max power 80. After cutting, I used a Vernier caliper to measure the total width of the cut sections. To find the actual kerf we need to divide the number we got by 2.

Final kerf: 0.09mm

Designing the file

Laser cutting the design and calculating using Vernier caliper

Errors and learnings

At first, I tried cutting the test piece on MDF, but it didn’t cut through due to incorrect laser settings. Thinking I could just restart the cut, I left the origin unchanged and hit the button again. Big mistake! Since I was measuring the kerf, cutting twice meant the kerf would change, making my measurements useless. Lesson learned: when calculating kerf, precision is key, and a single clean cut is a must.

Joints¶

What Are Joints?

Joints are the connection points between two or more parts in a design, allowing them to fit together securely.

The Role of Kerf in Joints

When designing joints for laser cutting, kerf (the material removed by the laser) plays a crucial role. If kerf is not considered, the joints may be too loose or too tight. For example, if a slot is designed as 3 mm wide but the laser removes 0.2 mm of material, the actual slot will be wider than intended, leading to a loose fit. To ensure accuracy, the joint dimensions must be adjusted by subtracting the kerf from the material thickness.

Types of joints

Press fit: A press-fit joint relies on a tight fit between two pieces. The slot size is slightly smaller than the tab to create friction, holding the parts together without glue or screws.
Chamfer joint: A chamfer joint has slanted (angled) edges, making it easier to insert and align the pieces.
Flexure joint: A flexure joint is designed to allow controlled bending. It uses thin, flexible sections in rigid materials, allowing movement without additional hinges or pins.
Pinned joint: A pinned joint connects two parts using a pin, allowing rotation or movement.
Finger joint: A finger joint consists of interlocking rectangular tabs that increase the contact area between two pieces.
Snap-fit joint: A snap-fit joint has flexible clips or hooks that lock into place when pressed together.
Wedge joint: A wedge joint uses a slanted piece (wedge) to lock two parts together. As the wedge is inserted, it tightens the connection, creating a strong and secure joint without glue or screws.

Parametric Design¶

What is Parametric Design?

Parametric design allows easy modifications by defining variables instead of manually adjusting dimensions. This is especially useful for laser cutting, where material thickness and kerf need frequent adjustments.

Creating a Parametric Construction Kit

For my parametric construction kit, I decided to create a star-shaped piece using just a circle and a triangle. The idea was to create a form that can be used by kids as toys or like a puzzle piece.

So I started off by starting the sketch and drawing a circle and triangle which will be my main two components. Next, I applied the parameters—Material Thickness, Kerf, and Slot Thickness to make the design adaptable.

After that, I created a slot with the thickness defined by the Slot Thickness parameter to ensure a proper fit.

Once the slot was ready, I used the Circular Pattern tool to duplicate both the triangle and the slots around the circle, forming a star-like structure.

Then, I extruded the design to give it depth, turning the 2D sketch into a solid 3D piece.

Finally, I applied a chamfer to smooth the edges, ensuring better aesthetics and usability.

After this, I selected the top surface of the 3D model and projected it onto a new sketch to create a clean 2D outline for laser cutting. Once the projection was done, I exported the file as a DXF, making it ready for fabrication with the laser cutter. Over here I used the Project tool to make sure the DXF file had the exact shape and size of my design.

Cutting and Assembling

The setting is speed: 12, min power:60, max power: 75

First I did a test cut of my main three pieces to see if the slot is correct

Then I assembled my final pieces. I was able to assemble it in various different variation. Following is my favourite one!